Quantitative estimation of phycocyanin concentration using MODIS imagery during the period of cyanobacterial blooming in Taihu Lake.

On the basis of the spectral characteristics of cynobacteria, a robust semi-empirical model was developed estimate phycocyanin concentration(Cpc) using MODIS imagery with a spatial resolution of 250m.The floating neonat cyanobacteria could be identified well and truly by the estimation model of Cpc.So it was easy to retrieve the coverage floating neonatal cyanobacteria from MODIS imagery by the model, where there was not any actual meaning quantitatively estimate Cpc and it was certainly not necessary to pay attention to its estimation precision.In the outside the newly cyanobacterial blooms-covered area, the Cpc estimation precision was highly determined by phycocyan pigment content and the ratio of Cpc to chlorophyll-a concentration(Chl-a).When Cpc was less than 35μg/L, the relati estimation error of the model was about 134% on average;and when it was more than 35μg/L, the relative error w reduced to 31%.However, when Cpc was more than 35μg/L and the ratio of Cpc to Chl-a was less than 8, the relati error was only up to 29% on average.